CHICAGO (AP) — Author Frederik Pohl, who over decades gained a reputation of being a literate and sophisticated writer of science fiction, has died at age 93.

His wife, Elizabeth Hull, said Tuesday that Pohl died Monday at a hospital after experiencing respiratory problems at his home in the Chicago suburb of Palatine. News of his death was first announced by his granddaughter, Emily Pohl-Weary, in a tweet.

Pohl wrote more than 40 novels. Two of his better-known works were “The Space Merchants,” written in the early 1950s with Cyril M. Kornbluth, and 1978′s “Gateway,” a winner of the Hugo Award for science fiction writing. Pohl was a literary agent and editor before getting his own work published in science fiction magazines of the 1930s. He’s credited with launching the careers of James Blish and Larry Niven.

“It is difficult to sum up the significance of Frederik Pohl to the science fiction field in few words,” Pohl’s editor James Frenkel said in an obituary released by the family. “He was instrumental to the flowering of the field in the mid-to-late 20th century, and it is hard to dispute that the field would be much the poorer without his talent and remarkable body of work as a magazine and book editor, a collaborator and a solo author.”

Pohl’s career began in 1937 with the sale of a poem, “Elegy to a Dead Satellite: Luna,” to Amazing Stories magazine. He went on to edit Astonishing Stories, Super Science Stories, Galaxy and If magazines, as well as an original anthology series, Star Science Fiction. As a book editor, he worked on Samuel R. Delaney’s “Dhalgren” and Joanna Russ’s “The Female Man.” As a literary agent, Pohl represented Isaac Asimov, Algis Budrys, Hal Clement, Fritz Leiber and John Wyndham.

Pohl was born in New York City in 1919. Despite dropping out of high school, his ambition was to be a professional writer. Friends described him as an avid reader, who read the works of Tolstoy in addition to science fiction magazines.

He served in the U.S. Army during World War II and was stationed in Italy, and after his discharge wrote advertising copy for a mail order publisher. After becoming a literary agent again, Pohl helped Asimov publish his first novel “Pebble in the Sky” in 1950. Although he devoted much of his time to writing in the 1970s, he also was science fiction editor at Bantam Books.

In 2009, Pohl launched “The Way the Future Blogs,” in which he wrote about his life, the science-fiction community, science and championed progressive politics.

Elizabeth Hull, English professor emerita of William Rainey Harper College and his wife of 29 years, said his remains will be cremated and a memorial service will be held at a future date.

Along with his wife, Pohl is survived by a son, three daughters and several grandchildren and great-grandchildren.